Aerobic exercise such as walking is a highly effective way to lose weight because your whole body is involved. Aerobics also get your heart pumping, and this cardiovascular exercise can improve heart and lung health over time. Unlike running, walking doesn't force you to repeatedly pound your feet on the pavement and risk injuring tender joints. While conventional fitness wisdom indicates that walking fast burns more calories, there's some evidence that walking slowly might be a better choice for some people.

Conventional Wisdom

Most doctors and fitness experts believe that faster speeds equal a greater number of calories burned. The reason for this is simple. When you're walking more quickly, your muscles have to work harder to maintain your pace. Your heart has to pump faster to supply your muscles with blood, and your lungs work harder to ensure that your blood is oxygenated. This extra work increases your cardiovascular benefits when you walk quickly.

New Research Directions

A 2005 study published in "Obesity Research" found that, for some people, walking slowly might actually increase the number of calories burned. Obese women burned more calories when they walked more slowly, and researchers found that this might be due to more efficient use of their energy. The study did not look at men and has not yet been replicated. Consequently, it's not conclusive. However, if you're overweight and have trouble walking long distances, walking more slowly could enable you to burn more calories by helping you walk longer.

Calories Burned

Until more research is done, it's probably safe to assume you'll burn more calories by walking quickly, particularly if walking quickly doesn't interfere with the length of time you spend walking. Your weight, muscle mass and overall health can affect how quickly you burn calories, but, on average, heavier people burn more calories than lighter people. At 3.5 miles per hour, a 125-pound person will burn about 120 calories in 30 minutes, while a 150-pound person will burn 149 calories. If you pick up the pace to 4.5 miles per hour, you'll burn about 150 calories at 125 pounds or 186 calories at 150 pounds.

Increasing Weight Loss

If you want to rev up your walking routine, one excellent way to do it is through interval training. Interval training also splits the difference between conflicting research and allows you to walk both quickly and slowly. Simply alternate paces every minute or so throughout your walk and, for maximum benefits, alternate between running and walking. Hill walking can also increase the number of calories you burn because it challenges your muscles more.

About the Author

Van Thompson is an attorney and writer. A former martial arts instructor, he holds bachelor's degrees in music and computer science from Westchester University, and a juris doctor from Georgia State University. He is the recipient of numerous writing awards, including a 2009 CALI Legal Writing Award.